Research On Key Technology Of Polarization And Multi-modal OAM In Wireless Communication

Polarization and orbital angular momentum are the two basic physical characteristics of electromagnetic wave in addition to the amplitude, phase and frequency. In the wireless communication system, using the polarization signal and the multi modal orbit angular momentum processing will open up two new dimensions of the utilization of the radio spectrum resources, and it also can improve and enrich the analysis,processing and transmission of wireless signals, to a large extent, it can ease the prominent problem effectively that the current limited spectrum resources become increasingly scarce. At the same time, it also opens up a new way to solve the problem of improving the capacity in the future of wireless communication system that the integration of heaven and earth,the integration of heterogeneous networks, the green and the energy saving of the wireless communication system. However, the introduction of the new technology needs to improve, optimize or re study and design of the traditional multi-dimensional modulation technology and its constellation mapping, system reuse method, etc.The topic of this thesis comes from the National Natural Science Fund Project "Research of power amplifier energy efficiency based on cognitive and polarization signal processing" (project number: 61271177) and"Research on the application mechanism of multi modal orbital angular momentum in the cognitive radio network with polarization diversity"(project number: 61561039). This paper mainly studies the multi-dimensional modulation processing technology of the polarization signal application of multi modal orbital angular momentum of electromagnetic vortex wave in polarization diversity. The main research and achievements are as follows:(1) This paper summarizes and analyzes the research on polarization signal processing and multi modal multiplexing technology of electromagnetic vortex wave. First outlined the characterization method of polarization, and then analyzed the challenge for the polarization and the orbital angular momentum of signal processing technology and its research contents in the wireless communication system, finally, classification combing the development status of the polarization and the orbital angular momentum of signal processing technology. What's more, on the basis of this, the problems that have not been solved are analyzed.(2) Aiming at the problem of channel depolarization effect, the paper proposed a new multi-antenna polarization channel model based on geometrical scattering theory. The method to determine the cross-polarization function that depended on spatial geometric relations between the transmitter and the receiver, and by consider the application scenarios of mobile or fixed communication nodes, A multi-antenna polarization channel scattering model is established, which is under the scene of fixed to mobile and mobile to mobile, then simulation analysis of the model. The simulation results show that compared with the polarization channel modeling method based on ray tracing, the modeling method described in this paper has lower algorithm complexity and ability to quickly restore polarization scattering scenes.(3)The paper starts from the objective of reducing the complexity of the system and increasing the robustness of the system,a kind of new polarization quadrature amplitude modulation system and the structure of three dimensional modulation mapping is proposed. The method using the unit Poincare ball and the three dimensional lattice structure. The paper give the structure of three dimensional modulation mapping with different orders by considering the share of the above parameters in different modulation orders, the theory proved that the structure in the feasibility of reducing the bit error rate of the system and analyzing and comparing the bit error rate of different structures. The analysis and simulation results show that the proposed three dimensional modulation constellation mapping structure can not only make full use of the polarization parameters,but also greatly reduce the complexity of the system.(4) The design of broadband micro-strip array antenna is studied in this paper according to the narrow bandwidth of micro-strip antenna, the L type probe fed micro-strip patch antenna is used as the element of the antenna, application of OAM technology in antenna array by changing the feed phase difference between the array elements. This paper designs a kind of 8 array element multi mode OAM electromagnetic vortex wave micro-strip array antenna structure, which works in L band. The working frequency band of the antenna is 1.35GHz?1.86GHz, and the relative bandwidth is 31.8%, at the same time, it is able to generate electromagnetic vortex waves with multiple OAM modes(l=0, l=±1, l=±2, l=±3) at the same frequency.